The girl, whose parents sell live poultry, was admitted to the hospital Thursday with pneumonia and is the first case reported outside eastern China, where the virus was first reported in late March.

Government officials said the total number of new bird flu infections across the country rose to 47 today as the eastern province of Jiangsu reported two fresh cases and shanghai reported one, The Associated Press reported.

What is concerning about this latest report is the distance between Shanghai and Beijing.

The virus was able to travel more than 750 miles without leaving a trail of dead birds.

Unlike the H5N1 bird flu that raised concerns starting in 2003, H7N9 does not seem to make birds very sick or sick at all. This makes tracking the movement of the virus and containing it to limited flocks of birds next to impossible.

You can't just test sick flocks. This case of bird flu in Beijing illustrates that clearly. This means that to understand where people might be at risk, China will have to screen a lot of healthy birds across an increasingly large area.

The epidemiologic investigations of people who were sickened by H7N9 are extremely important. In order to prevent infections, we need to understand what kind of exposures put people at risk.

Are there particular types of birds that are implicated? For those people with no apparent bird contact, how did they get infected? This information is essential if one is to begin to think about rational control strategies.